Field of the Invention
The present invention relates to a replaceable-type ink-jet ink tank cartridge connected to an ink-jet head and storing the ink to be discharged from the ink-jet head, a method for manufacturing said tank, and a package container for the ink tank cartridge.
Also, the present invention relates to an ink-jet ink tank cartridge having a specific internal structure, and a manufacturing method thereof, as well as an ink-jet head using the ink tank cartridge, and a printer (recording apparatus). The present invention is applicable to recording apparatuses, communication equipments, business machines, composite apparatuses, and printers such as e.g., a copying machine or a facsimile apparatus, using an ink-jet technology.
In recent years, ink-jet recording apparatuses have been utilized for a great variety of applications, and there are uses for the output of high duty image of large size and graphics or photo grade, with increasing demands.
On one hand, there is rapidly increasing utilization for smaller or personalized output apparatuses, while having greater output frequency (use frequency), resulting in more and more increasing print volumes in those applications.
In any way, in the ink-jet print field, there is a tendency toward the larger size, higher duty, and higher use frequency, and due to increased ink consumption, there is increasing demand for the greater capacity of ink tank for the purposes of reducing the frequency of replacing the ink tank cartridge for use in the recording apparatus, and avoiding the damage of head filter. In particular, there is a demand to take not only a simple measure of increasing the size of ink tank cartridge, but also to create a larger capacity of ink tank for the recording apparatus for which the smaller and personalized constitution has been achieved, with the compatibility maintained, for which it has been contemplated that the size of tank cartridge is increased and the shape of tank is altered.
Herein, one form of the ink tank cartridge to increase the ink amount has been proposed in which a first storage chamber for containing the ink, and a second storage chamber for containing the ink, are formed, with a negative pressure generating member such as a sponge provided within the first storage chamber.
The first storage chamber having a negative pressure generating member is provided with an atmosphere communicating opening for communication with the atmosphere, in which an area around the atmosphere communicating opening within this first storage chamber is one where the negative pressure generating member does not hold the ink. Also, this first storage chamber is provided with an ink supply port for supplying the ink held within the negative pressure generating member to an ink-jet head of an ink-jet printing apparatus. The second storage chamber is in communication with the first storage chamber only via a fine communication channel provided at a position apart from the atmosphere communicating opening of the first storage chamber, and stores the ink in a substantially enclosed state. And when using an ink cartridge, the exchange of gas and liquid is made via the fine communication channel between the first and second storage chambers, so that the ink is refilled from the second storage chamber via the fine communication channel into the first storage chamber.
By the way, in the ink-jet printing apparatus, when a plurality of ink-jet heads are mounted on a carriage to reduce the number of line buffer memories, the distance between ink-jet heads is set to be smaller in a scan direction of the carriage in most cases, whereby there are necessarily limitations on the width of ink cartridge when the ink cartridge is mounted on the carriage. Hence, the ink capacity is increased in the height and depth directions of the ink cartridge. Also, to make the foot space of the ink-jet printing apparatus smaller, it is desirable that the ink capacity can be increased only by increasing the height of ink cartridge.
However, in an ink cartridge of the structure of holding the ink soaked within the negative pressure generating member, the water head applied on the ink-jet head is prone to rise in accordance to an increase in height, when the height of ink cartridge is increased, and to prevent this, if the density of negative pressure generating member is raised one-sidedly, the remaining ink amount not used within the ink cartridge increases, making it difficult to expect the effective increase of ink amount corresponding to the increased capacity.
Also, in making such ink tank cartridge of greater capacity, the following affairs may be apprehended.
(1) The air within the second storage chamber will expand due to changes in temperature or pressure when the ink within an ink cartridge is used partially, forcing the ink within the second storage chamber to be flowed into the first storage chamber. Then, it is impossible to expect that the negative pressure is generated by the negative pressure generating member within the first storage chamber, resulting in a positive pressure state. As a result, an adverse effect may be exerted on the formation of meniscus around the ink discharge orifices during the printing or recording or after a suction recovery operation. Herein, by the suction recovery operation is meant an operation of sucking and removing the thickened ink from the ink discharge orifices of ink-jet head.
(2) If the ink capacity is increased, the ink may swell out from the negative pressure generating member of the first storage chamber, mainly due to temperature change (particularly expanded ink volume at low temperatures) during the physical distribution of ink cartridges. Depending on the attitude of ink cartridge in the physical distribution, the ink may not return to the negative pressure generating member, when the temperature rises, accumulating around the atmosphere communicating opening, in which case the ink is more likely to leak and drip when the ink cartridge is unsealed. Also, it is apprehended that when the ink in the positive pressure state is supplied to the ink-jet head, an adverse effect may be exerted on the print performance such as recording.
(3) Even with a slight phenomenon of the above (2), in place of the ink forced from the second storage chamber into the first storage chamber, the air will be moved from the first storage chamber through the fine communication channel into the second storage chamber, by a corresponding amount of ink, whereby when the ink cartridge is unsealed after a rapid increase in temperature or a decrease in pressure, the ink forced from the second storage chamber into the first storage chamber due to expanded air can not be accepted by the negative pressure generating member, with a risk that the ink may exude outside via the atmosphere communicating opening. Also, when unsealing an ink supply port, a portion around the ink supply port within the first storage chamber is in positive pressure state, with a risk that the ink may also leak out of the ink supply port.
Also, if the ink tank cartridge is constructed in larger size (scale up), the negative pressure generating member is also increased in size, resulting in a greater distance from the ink storage chamber to the ink supply port. That is, the larger ink tank will have a greater distance from the communication channel to the supply port, and further be subjected to the influence from the uneven density accompanied by the larger size of the negative pressure generating member accommodated within the negative pressure generating member receiving portion, with a risk that the ink level is not stable, leading to an ink supply failure in worst cases.
Also, an non-ink region within the negative pressure generating member not containing the ink is intended to prevent the ink from leaking through the atmosphere communicating opening, when starting to use the ink tank, but this non-ink region occupies a large area with increasing size of the cartridge, thereby with a risk that the same problem of ink supply failure as above may occur. Namely, in this way, if the ink cartridge is subject to the influence of changes in environment due to storage or physical distribution in the state where the non-ink region is large, the ink is moved to the non-ink region within the negative pressure generating member, resulting in a likelihood that an ink absent portion may arise in a range from the communication channel to the supply port.
On the contrary, it is considered to shorten the distance from the communication channel to the supply port, in which case the initial ink level within the negative pressure generating member is too high compared with the total volume of negative pressure generating member, and to retain this initial ink level, it is necessary to significantly raise the capillary force of negative pressure generating member, with the result that the negative pressure on the recording head is too great, inappropriately for the fast recording. Also, the large amount of ink may remain.
The ink-jet ink cartridge having larger size and more complicated shape as above described must satisfy the ink-jet performance at the same time. That is, the ink-jet ink cartridge is required to have the sealing ability without ink leakage which is assured for use in the high/low temperature environment or the long-term storage, and various external factors including a mechanical strength against thermal shock caused by repeated high/low temperatures, vibration, or drop, as well as quite severe characteristics of stably storing the ink and without damaging the ink supply capability in use for recording or the negative pressure exerted on the recording head, as previously described.
For such requirements, a method of forming an ink container is known in which two members, a container having integrally molded a partition plate for partitioning the negative pressure generating member receiving portion and the ink containing portion, and a lid, are integrated by fusing a joint by heat or ultrasonic.
However, a heat welding method could not be applied to the ink cartridge of such a complex shape that the joint extends into the tank, because the joint must be exposed to the outside for welding. Accordingly, the container of integral mold was molded in the configuration having the partition plate and the wall within the container connected. Also, a ultrasonic welding method in which ultrasonic is applied to the joint to weld by heat generated by thermal conversion of acoustic wave due to energy loss at the joint is difficult to make a perfect contact state over the entire area of welding portion due to the dimensions of parts if the size is increased, because the contact state at the joint has a dimensionally severe factor.
On the other hand, in the conventional ink tank as previously described, one package in which a seal member of the atmosphere communicating opening and the ink supply port of the ink tank is adhered to a pillow bag in packaged form was proposed in Japanese Laid-Open Patent Application No. 6-328712. In this packaged form, the ink, if splashing due to a peeling force from the seal member peeled off in unsealing the package, is received into the bag, while the package is unsealed in the order from the atmosphere communication opening, without the user considering the unsealing order of the atmosphere communicating opening and the ink supply port.
In the conventional form, when the ink capacity of ink tank is relatively small, the internal pressure of ink tank may rise, owing to changes in environment (pressure, temperature) surrounding the ink tank at the time of manufacturing or unsealing. Then, if the ink tank is unsealed, the ink may be forced out of the ink tank. This ink amount will vary with the total capacity of ink for the ink tank. It increases with larger capacity of ink tank. Since the ink tank is desired to have larger capacity, the amount of splashing ink may be serious in the conventional packaged form, if the larger capacity is provided, so that there are some cases that the ink can not be held within the pillow bag.
Also, with the larger amount, the ink may enter, due to capillary phenomenon, into an interstice between the ink tank and the pillow bag, resulting in greater probability that the ink reaches the hands of the user who holds by hand the ink tank.
Further, in the form of pillow bag, the user may neglect the way of unsealing, break the bag open and peel off a scal member for sealing the atmosphere communicating opening and the ink supply port of ink tank.
In this case, in peeling off the seal member, the ink may splash from the seal member upon an impact of peeling in some instances.